Method for processing sheet material such as bank notes using a sorting tree

ABSTRACT

The method involves measuring data of a sheet material first being detected by means of a sensor, the sensor then deriving one or more measuring results from the data. Using a sorting tree a sorting class for the sheet material is derived from the measuring results of the sheet material. In each sorting node of the sorting tree a domain is fixed for at least one measuring result. The domains of a measuring result in a sorting node are selected so that they are either a subdomain or equal to the domain of the corresponding measuring result of the assigned, higher sorting node. The sheet material is transported to a destination in accordance with the derived sorting class for the sheet material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for processing sheet material such asbank notes.

2. Description of Related Art

A method for processing sheet material such as banknotes by detectingmeasuring data by means of at least one sensor; deriving measuringresults from the detected measuring data, and deriving a sorting classfor the sheet material from the measuring results, wherein the step ofderiving the sorting class for the sheet material comprises the step oflocating a sorting node in a sorting tree in which all of said measuringresults are within predetermined ranges of values, herein after referredto as domains, and wherein the sorting tree has the followingcharacteristics:

domain is fixed at least for one measuring result in each sorting nodeof the sorting tree,

for a domain of a measuring result in a sorting node of the sorting treewhich is not the uppermost sorting node of the sorting tree, acorresponding domain of this measuring result is present in theassigned, higher sorting node, and

the domain of a measuring result in the sorting node is a subdomain orequal to the domain of the corresponding measuring result of theassigned, higher sorting node,

is known from DE-OS 27 60 166 for example. Using a singler the sheetmaterial present in a stack is separated into single sheets anddelivered to a transport path which transports the singled sheetmaterial through the apparatus.

A plurality of sensor units are mounted along the transport path, eachsensor unit detecting measuring data of certain features of the sheetmaterial and combining them into a measuring result. The structure ofthe sensor units used here is shown in DE-PS 27 60 165. Each sensor unithas a transducer that detects certain features of the sheet material andconverts them into an electric signal. This signal is transformed in asignal processing stage. The usually analog signal is generallyconverted into digital measuring data here. The measuring data are thentransformed into yes-or-no information in an evaluation unit of thesensor unit. This information constitutes the measuring result of thesensor unit and is stored, assigned to the particular sheet material, ina main memory.

The main memory is used as a connection for data exchange between theunits of the apparatus. It can be accessed by all units which write orread the data necessary for processing the sheet material. One datarecord is stored in the main memory for a plurality of sheets in eachcase.

From the measuring results of the sensor units stored in the main memoryfor each sheet material, evaluation information is first produced in acentral evaluation unit. A decision table stored in the evaluation unitis used to determine the destinations for the particular sheet materialfrom the evaluation information. The destinations can be for examplestackers for stacking the sheet material or shredders for destroying thesheet material. The destinations for the corresponding sheet materialare also stored in the main memory. With reference to the storedinformation on the destination the sheet material is guided accordinglyby the transport unit and the actual deposit checked.

In the known system, the sensor units deliver only yes-or-no informationas a measuring result. For sensor units whose measuring results are notrestricted to yes-or-no information but equipped with a higherinformation content, such as the length or width of the sheet materialin mm, a dimension figure for the soiling or the like, the production ofa decision table for deriving a sorting class or destination for thesheet material is elaborate and relatively quickly becomes too intricateand therefore error-prone.

SUMMARY OF THE INVENTION

On these premises, the invention is based on the problem of proposing amethod for processing sheet material which makes it possible to processmeasuring results with higher information content and to derive asorting class for the sheet material from these measuring results in asimple and reliable way.

The basic idea of the invention consists in determining the derivationof a sorting class from the particular measuring results obtained for asheet material with reference to a sorting tree. The structure of thesorting tree, i.e. the number of nodes and the number of hierarchicallyarranged levels, can be very different depending on the number ofdesired sorting classes and the particular task to be performed inevaluating the sheet material. Two branches of the inclusion graph ofthe sorting tree can converge again if they are not disjunct in terms ofset theory. A task to be performed can be for example to sort a stack ofmixed bank notes according to the particular denomination and accordingto soiled and unsoiled notes in the particular denomination. In any casea domain is fixed at least for one measuring result in each sorting nodeof the sorting tree. Except for the uppermost sorting node of thesorting tree, for each domain of a measuring result in a sorting node ofthe sorting tree a corresponding domain of this measuring result isprovided in the assigned, higher sorting node. The domain of themeasuring result in the sorting node is either a subdomain or equal tothe domain of the corresponding measuring result of the assigned, highersorting node. A domain is preferably fixed for each measuring result ineach sorting node of the sorting tree.

The advantage of the method is that the introduction of domains makes itpossible to process measuring results with higher information content.The neat structure of the sorting tree ensures that errors in producingthe sorting tree can be very largely avoided, and a sorting class can bederived for the sheet material in a simple and reliable way using thesorting tree. The high flexibility of the sorting tree readily permitsadaptation to different tasks to be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of an apparatus for processing sheetmaterial,

FIG. 2 shows a schematic diagram of a sorting tree,

FIG. 3 shows a table of some exemplary properties of the sheet material,

FIG. 4 shows a value space of a two-dimensional sorting tree,

FIG. 5 shows a schematic diagram of the two-dimensional sorting tree,

FIG. 6 shows a table of domains of the sorting nodes,

FIG. 7 shows a table of domains of the report nodes,

FIG. 8 shows a value space of a two-dimensional sorting tree with afirst way of generating report spaces,

FIG. 9 shows a value space of a two-dimensional sorting tree with asecond way of generating report spaces,

FIG. 10 shows a table of subspaces,

FIG. 11 shows a table of value spaces of the report nodes for the firstway,

FIG. 12 shows a table of the value spaces of the report nodes for thesecond way,

FIG. 13 shows a schematic diagram of a rule matrix.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic diagram of an apparatus for processing sheetmaterial. The apparatus has control device 10 connected via data line 20with number L of sensors 30.1 to 30.L.

Sensors 30.1 each have transducer 31.1 that detects certain features ofthe sheet material and converts them into electric signals. Thesesignals are then converted into digital measuring data MD andtransferred to evaluation unit 32.1. The latter derives at least onemeasuring result ME from measuring data MD of transducer 31.1. Measuringresults ME derived from sensors 30.L are then transferred to controldevice 10. Control unit 10 receives number N of measuring results MEfrom sensors 30.L and derives from measuring results ME¹ to ME^(N) of asheet material a sorting class for the corresponding sheet material.With reference to the derived sorting class sorting destination 40.m isassigned to the sheet material from number M of sorting destinations.The sorting destinations can be stackers, shredders or the like. Thesorting destinations each have detecting device 41.m with which theydetect the sheets intended for them.

For deriving the sorting class of a sheet material one first produces asorting tree which is stored in control device 10. A schematic diagramof a sorting tree is shown in FIG. 2. Starting from uppermost sortingnode K₀, number K of sorting nodes K₀₁ to K_(0K) are assigned to thisnode. The index of the sorting node describes the level or depth of thesorting tree and the assigned, higher sorting node. The number ofindexes stands for the level of the sorting tree or for the depth of thenode. One index signifies the first level, two indexes the second level,etc. The uppermost sorting node is on the first level and has the index0. The nodes assigned to the uppermost sorting node are one level underthe uppermost sorting node, i.e. on the second level, and therefore havetwo indexes. The first index shows the index of the parent node, and thelast and second index numbers the assigned nodes from 1 to K. Theindexes of the nodes shown on the third level are obtained analogously.Node K_(02Q) therefore designates the Qth node which is assigned to nodeK₀₂.

For each sorting node K of the sorting tree, domains are fixed for eachmeasuring result ME¹ to ME^(N). The domains are intervals with lowerlimit a and upper limit b. The limits are designated above with theindex of the corresponding measuring result and below with the index ofthe corresponding node. The domains in uppermost node K₀ can inprinciple be selected at will. However, it is advantageous to select thedomains so that the corresponding domain of a measuring result comprisesthe totality of possible measuring results.

The domains of a measuring result in a sorting node which is notuppermost sorting node K₀ of the sorting tree are either a subdomain orequal to the domain of the corresponding meameasuring result of theassigned, higher sorting node. For the interval limits of the secondlevel it therefore holds that a^(n) ₀>=a^(n) _(0k) and b^(n)_(0k)<=b^(n) ₀. It holds analogously for example for nodes K₀₂₁ toK_(02Q) subordinate to node K₀₂ that a^(n) ₀₂>=a^(n) _(02q) and b^(n)_(02q)<=b^(n) ₀₂.

Since the domains of the individual measuring results thus generallybecome smaller with the depth of the corresponding sorting nodes andthus describe the sheet material more and more exactly, the nodesconstitute a classification of the measuring results into sortingclasses. The corresponding sorting class is stated in parentheses afterthe node designation in FIG. 2. Uppermost sorting node K₀ is assignedthe sorting class “reject” here, sorting node K₀₂ for example thesorting class “10 DM, unfit,” and sorting node K₀₂₁ the sorting class“10 DM, fit.” The sorting classes each constitute a verbal descriptionof the limits of certain properties as described by the domains of thecorresponding node.

FIG. 3 shows some properties with their possible domains by way ofexample. The individual domains can have different qualities. Theproperty “denomination” can for example assume five discrete values,while soiling, dog-ears or stains can assume any value in a certaininterval between 0 and 100%. Properties such as position, securitythread or watermark have only two discrete values.

The designation of the sorting classes is selected here so that one canapproximately deduce the domains of at least some properties. The term“fit” can mean for example that the percentages of soiling, dog-ears andstains of the bank note are low. The term “unfit” means that thepercentages of these properties are high. Since denomination is adiscrete property it is stated with its corresponding value directly inthe nodes. The sorting class “reject” is interpreted in such a way thatthis sheet material cannot be processed properly by the apparatus.

In order to assign a sheet material a sorting class one looks in thesorting tree for the sorting node in the deepest level at which allmeasuring results ME¹ to ME^(N) of the sheet material are within thecorresponding domains of the measuring results of the sorting node. Thedomains of the sorting nodes are preferably checked recursively, i.e.starting out from uppermost sorting node K₀ one checks whether there isa sorting node in the first level at which all measuring results of thesheet material are within the corresponding domains of the measuringresults of the sorting node. If this is the case, the sorting nodesassigned to this node in the third level are checked in the same way.One thus analogously determines the node which is located in the deepestlevel of the sorting tree and at which all measuring results of thesheet material are within the corresponding domains of the measuringresults of this sorting node. The sheet material is then assigned thesorting class of the determined sorting node.

If in a level there are several sorting nodes at which all measuringresults of the sheet material are within the corresponding domains ofthe measuring results of the sorting nodes, these sorting nodes arepreferably checked in a fixed order.

The sorting nodes are thus generally first checked in the depth of thesorting tree and then the sorting nodes within a level of the sortingtree.

For example, for a sheet material whose measuring results are within thecorresponding domains of the measuring results of sorting node K₀₂₁ withsorting classes “10 DM, fit,” it is first checked whether the measuringresults of the sheet material are within the corresponding domains ofthe measuring results of sorting nodes K₀₁. This is not the case,however, since the value of the denomination is different. Since thedomains of nodes K₀₁₁ to K_(01P) subordinate to sorting node K₀₁ aregenerally smaller than or at most equal to the corresponding domains ofthe measuring results of sorting node K₀₁, none of these nodes candescribe the sorting class suitable for the sheet material, so thatthese nodes need not be checked further.

It results for sorting node K₀₂ that all measuring results of the sheetmaterial are within the corresponding domains of sorting node K₀₂. Thesorting tree is thus first processed further in its depth. In the fixedorder sorting node K₀₂₁ is then first checked and it is ascertained thatall measuring results of the sheet material are within the correspondingdomains of the measuring results of sorting node K₀₂₁. Since node K₀₂₁is not assigned any further sorting nodes here, the sheet material isassigned the sorting class of sorting node K₀₂₁, i.e. “10 DM, fit.”There is no firther check of nodes K₀₂₁ to K_(02Q) whose order is aftersorting node K₀₂₁.

Further, each sorting node is assigned value space W defined as theCartesian product of all domains of the measuring results fixed in thesorting node. For sorting node K₀ it holds for example that W(K₀)=[a¹ ₀,b¹ ₀]×[a² ₀, b² ₀]× . . . ×[a^(N) ₀, b^(N) ₀]. One proceeds analogouslyfor all other sorting nodes.

To increase the efficiency of the method further, the value spaces ofthe sorting nodes which are assigned to another sorting node areselected so that they are disjunct. For example, nodes K₀₁ to K_(0K) areassigned to sorting node K₀. The domains of sorting nodes K₀₁ to K_(0K)are now selected so that the corresponding value spaces of sorting nodesK₀₁ to K_(0K) are disjunct. For the value spaces of sorting nodes K₀₁₁to K_(01P) which are assigned to sorting node K₀₁, and the other sortingnodes one proceeds accordingly. The advantage of such a definition ofthe domains in the sorting nodes is that the check of the sorting treewith reference to the measuring results of a sheet material always leadsto the same sorting node independently of the order of processing of thesorting nodes within a level.

Further, each sorting node of the sorting tree can be assigned a reportnode, which differs from a sorting node only in that it is assigned areport message rather than a sorting class. A domain is also fixed foreach measuring result in each report node, the domain of the measuringresult in a report node being a subdomain or equal to the domain of thecorresponding measuring result of the assigned sorting node.

In contrast to the sorting nodes, a report node cannot be assigned anyfurther nodes. The set of report nodes assigned to a sorting node isdesignated R in FIG. 2. The upper indexes of the set of report nodes Rdesignate assigned sorting node K. The first indexes of a report nodedesignate, analogously to the sorting node, the higher, assigned sortingnode. The last index of a report node numbers the individual reportnodes assigned to the higher, assigned sorting node.

Analogously to the sorting node, each report node can be assigned avalue space defined as the Cartesian product of all domains of themeasuring results fixed in the report node. Each higher sorting node isnow assigned a sorting space defined as the union of all value spaces ofthe sorting nodes assigned to the sorting node, and a report spacedefined as the union of all value spaces of the report nodes assigned tothe sorting node.

The domains of the measuring results in the report nodes are preferablyfixed in such a way that the report space and the sorting space of thesorting node are disjunct. The report space is in turn preferablyselected additionally in such a way that the union of report space andsorting space of a sorting node yields the value space of the sortingnode. This procedure ensures that each sheet material can be assignedeither a sorting node or a report node with reference to its measuringresults.

If all measuring results of a sheet material are within thecorresponding domains of the measuring results of a report node, thesheet material is assigned not only the report message but also thesorting class of the higher sorting node.

If the value spaces of all report nodes of a sorting node are selectedto be disjunct, one obtains a definite report message for each sheetmaterial in accordance with the measuring results. However, it isgenerally unnecessary for the value spaces of all report nodes to bedisjunct. In this case it is possible for the measuring results of asheet material to fall within the value spaces of several report nodes.With the report nodes, in contrast to the sorting nodes, all reportnodes assigned to the sorting node are checked, so that in this case thesheet material can also be assigned the report messages of severalreport nodes.

In the following, an example will be given for a two-dimensional sortingtree, i.e. the sorting tree is based on only two measuring results. FIG.4 shows the value space of uppermost node K₀. The axes show measuringresult ME¹ (denomination) and measuring result ME² (soiling). Theproperty “denomination” is a property with five discrete values, whilethe values of soiling can vary continuously in a range from 0 to 100%.

The corresponding sorting tree is shown in FIG. 5. Starting out fromuppermost node K₀ this tree has on the second level two sorting nodesK₀₁ and K₀₂ and a set of report nodes R⁰ comprising four report nodesR₀₁ to R₀₄ here. Sorting node K₀₁ is assigned on the third level twosorting nodes K₀₁₁ and K₀₁₂ and a set of report nodes R⁰¹ with onereport node R₀₁₁. Sorting node K₀₂ is assigned on the third levelsorting node K₀₂₁ and a set of report nodes R⁰² with two report nodesR₀₂₁ and R₀₂₂. The domains for measuring results ME₁ and ME₂ assigned tothe sorting nodes are shown in the table in FIG. 6. The domains ofmeasuring results ME₁ and ME₂ of the report nodes are shown in the tablein FIG. 7.

The value spaces of the sorting nodes or report nodes resulting from thedomains are shown in FIG. 4. The value space of sorting node K₀ ismarked by the surrounding square. The value spaces of the sorting nodesof the second level of the sorting tree are shown hatched. The valuespaces of the third-level sorting spaces are marked in white, Thesecond-level report nodes are shown in dark gray and the third-levelreport nodes in light gray.

As one readily sees, the value spaces of the second-level sorting nodesare subsets of the value space of the first-level sorting node, and thevalue spaces of the third-level sorting nodes assigned to thesecond-level sorting nodes are in turn subsets of the correspondingvalue space of the assigned second-level sorting nodes. The requireddepth relation for the sorting nodes is thus ensured. Further, the valuespaces are disjunct within a level.

The value spaces of the report nodes are selected so that they aredisjunct from the value spaces of the second-level sorting nodes.Further, the union of the value spaces of all second-level nodes yieldsthe value space of assigned, higher sorting node K₀ so that themeasuring results of a sheet material are within the value space ofeither a sorting node or a report node of the second level. This appliesanalogously to the third-level nodes and the corresponding assignedsecond-level sorting nodes.

The above-described structure of the sorting tree ensures that thedomains of the measuring results in the individual nodes can only bechanged in certain areas. In order to prevent certain domains in thesorting nodes from being changed without authorization, the domainsand/or the interval limits of the measuring results in each node areeach assigned at least partly a security value. By means of thissecurity value one regulates under which conditions the assigned domainand/or interval limit can be changed. These conditions can depend e.g.on the operating state of the apparatus or the identity of the operator.For example, if an operator is not authorized to change domains and/orinterval limits of a certain measuring result, this domain and/orinterval limit can be protected in each node by a corresponding securityvalue.

A further way of protecting the sorting tree is to assign a securityvalue directly to certain nodes. Via this security value one canregulate for example under which conditions in the node certain domainsmay be changed. If certain domains are already protected by their ownsecurity values, the higher security value can be fixed for thecorresponding domain for example. Further, one can regulate by means ofthe security value under which conditions a node may be removed. It isalso possible to regulate via the security value under which conditionsa node may be assigned further nodes.

The assignment of security values in the sorting tree thus permitsmanipulations of the sorting tree to be controlled in a simple way, andperformed only by authorized persons with corresponding security values.

In order to avoid errors when changing interval limits of the domainswithin the sorting tree, the interval limits can be provided at leastpartly with a certain marking. If a marked interval limit is changed,all other interval limits provided with this marking are automaticallyalso changed accordingly.

This measure makes it possible to restrict the relatively great numberof degrees of freedom in selecting the interval limits of the individualdomains to a reasonable measure. Additionally, one can also protect themarkings of the interval limits from unauthorized changes by assigning asecurity value.

To simplify the production of a sorting tree further, it is possiblefirst to produce the tree structure of the sorting nodes including thefixing of the domains of the individual measuring results. The reportnodes assigned to the sorting nodes can be generated automatically. Thebasic idea here is that the sorting space and the report space of eachsorting node are disjunct and the union of sorting space and reportspace of a sorting node yields the domain of the sorting node.

Various ways of automatically generating report nodes are shown in FIG.8 and FIG. 9, the examples corresponding substantially to the examplefrom FIG. 4. As already shown in FIG. 5, sorting node K₀ is assigned twosorting nodes K₀₁ and K₀₂. The report space of sorting node K₀ is darkgray in FIG. 8 and the sorting space shown in light gray by the valuespaces of assigned sorting nodes K₀₁ and K₀₂.

For automatically generating the set of report nodes R⁰ one decomposesthe value space of sorting node K₀ along the dashed or dotted lines, thelines running in each case along the interval limits of the domains ofthe measuring results of assigned sorting nodes K₀₁ and K₀₂. Thisdecomposition yields seven subspaces U₀₁ to U₀₇ each designated in theupper right corner of the corresponding subspace. The domains ofsubspaces U₀₁ to U₀₇ are shown in the table of FIG. 10.

A way of automatically generating the report nodes is now to assign eachreport node one of these subspaces as the value space, and to select thedomains of the measuring results of the report node accordingly.

To keep the number of automatically generated report nodes as low aspossible, however, one preferably combines the subspaces suitably beforeassigning them to a report node.

A first way of combining them is shown in FIG. 8, those subspaces in areport node being combined whose domains are equal with respect tomeasuring result ME¹ (denomination) and whose domains of measuringresult ME² (soiling) are adjacent so that they can be combined into agreater domain. The report nodes arising from the combination ofsubspaces are shown in tabular form in FIG. 11. The limits betweenreport rules R which determines which domains are included in the reportnodes, and therefore the criteria on which the reports are based areshown by dash lines in FIG. 8, while the limits between two subspacesare shown by a dotted line.

In report node R₀₃ subspaces U₀₃, U₀₄ and U₀₅ are combined since thesesubspaces have equal domains with respect to first measuring result ME¹and the domains with respect to measuring result ME² are adjacent andcan thus be combined into a greater domain. In contrast, subspaces U₀₁and U₀₂ cannot be combined into a report node since they have equaldomains with respect to measuring result ME¹ but the domains withrespect to measuring result ME² are not adjacent and can thus not becombined into a greater domain.

A second way of automatically generating report nodes is shown in FIG.9. In contrast to the first way, one here combines the subspaces forwhich the domains of measuring result ME² are equal and the domains ofmeasuring results ME¹ are adjacent. Report nodes R′₀₁ to R′₀₃ resultingfrom the combination are shown in tabular form in FIG. 12. Here, too,the limits between the report rules are shown analogously by dash linesand the limits between the subspaces by dotted lines.

As one sees from the above example, both the number and the value spacesof the generated report nodes depend on the order in which the subspacesoccurring upon decomposition are combined. The automatically generatedreport message also depends on the order of processing of the measuringresults. For example in report node R₀₃ in FIG. 8 the automaticallygenerated report message could read “denomination.” One can thus derivefrom the report message only that the note with the sorting class ofsorting node K₀ was a bank note with a denomination which occurs in novalue space of an assigned sorting node. One can draw no conclusion onits soiling from this report message. The automatically generated reportmessage of report node R′₀₁ from FIG. 9 could read “soiling” forexample. However, this report message does not clearly indicate whichdenomination the sheet material had.

With this way of automatically generating report nodes it is thusdecisive in which order the measuring results are processed. It ispossible analogously to generalize this example for higher dimensionalvalue spaces, i.e. for any number N of measuring results. If required,it is also possible for the expert to apply other methods forautomatically generating report nodes.

In order to simplify the check of the sorting tree with reference to themeasuring results of a sheet material by control unit 10, the sortingtree including the automatically generated report nodes can be mappedonto a suitable form. Such a form is for example the rule matrix shownin FIG. 13.

For producing this rule matrix one decomposes the domain of eachmeasuring result defined in uppermost sorting node K₀ into adjacentpartitions, the partition limits containing at least interval limits aand b of the domains of the corresponding measuring results of all othernodes. For measuring result ME¹ (denomination) from the above exampleone obtains a decomposition of the domain of sorting node K₀ into fivepartitions with 5 DM, 10 DM, 20 DM, 50 DM and 100 DM. Measuring resultME² (soiling) is also decomposed into five partitions each comprisingthe intervals [0%, 20%], [20%, 40%], [40%, 60%], [60%, 80%] and [80%,100%].

The partition limits are preferably selected so that they are assignedonly to one partition. The partitions are thus disjunct and their unionyields the domain of sorting node K₀ of the corresponding measuringresult.

One can now derive the sorting rules of the rule matrix clearly from thedomains of the individual measuring results of each sorting node bymarking each partition which is at least a subset of the correspondingdomain of the measuring result of the sorting node. For sorting node K₀₁the partition 5 DM, 10 DM of measuring result ME¹ and the partition[60%, 80%] and [80%, 100%] of measuring result ME² are marked forexample. The union of the marked partitions of a measuring result inturn yields the domain of the measuring result of the correspondingsorting node.

The order of thus produced sorting rules depends on the processing orderof the corresponding sorting nodes of the sorting tree. One generallyprocesses the sorting rules corresponding to deeper sorting nodes beforethe sorting rules corresponding to the assigned, higher sorting nodes.Sorting rules corresponding to a sorting node assigned to anothersorting node are disposed in the order of the assigned sorting nodes.Each sorting rule is then assigned the sorting class of thecorresponding sorting node.

The report rules are produced and disposed analogously to the sortingrules. Each report rule is assigned the report message of thecorresponding report node.

Using such a rule matrix one can determine the sorting class or reportmessage in a simple way in accordance with the measuring results of asheet material. For example for a sheet material with the measuringresults (5 DM, 82%) one first marks the partitions in which themeasuring results of the sheet material are located. One obtainsmeasuring result vector V₁.

For deriving the sorting class one now compares the sorting rules intheir order with measuring result vector V₁ up to the rule in which thesame partitions are marked as in measuring result vector V₁, i.e. inthis case rule 2. The sheet material is now assigned the sorting classof sorting rule 2.

One then compares the report rules with measuring result vector V₁ anddetermines all report rules in which the same partitions are marked asfor measuring result vector V₁. In this example none of the markings ofthe report rules agrees with the markings of measuring result vector V₁so that the sheet material is not assigned any report message.

For a sheet material with the measuring result (50 DM, 48%) oneanalogously obtains measuring result vector V₂. Comparison with thesorting rules or report rules yields sorting rule 5 and report rule 3 sothat the sheet material is assigned the sorting class of sorting rule 5and the report message of sorting rule 3.

By reason of the described structure of the rule matrix it is thuspossible to derive a sorting class or one or more report messages fromgiven measured values for a sheet material in the simplest way.Automatic generation of the rule matrix from a sorting tree ensures thatthe neat structure of the sorting tree avoids errors in producing thesorting tree and thus in producing the rule matrix.

Along with the described structure of the rule matrix it is alsopossible for the expert to derive other representations of the sortingtree which can be processed by control device 10 in a simple way.Alternatively to the sorting tree, one can also use a flow chart of theform of representation for the user interface. The forms ofrepresentation, sorting tree and flow chart, are equivalent as regardscontent. The flow chart can thus be translated any time into aset-theoretical sorting tree, and vice versa.

What is claimed is:
 1. A method for processing sheet material,comprising the steps of: detecting measuring data by means of at leastone sensor; deriving measuring results from the detected measuring data,and deriving a sorting class for the sheet material from the measuringresults, wherein the step of deriving the sorting class for the sheetmaterial comprises the step of locating a sorting node in a sorting treein which all of said measuring results are within a predetermined rangesof values, said predetermined ranges being hereinafter referred to asdomains, wherein said sorting tree includes a plurality of sortingnodes, one of said sorting nodes being an uppermost sorting node and allother ones of said sorting nodes being directly connected to one uppernode and at least one lower node to form said sorting tree, saiduppermost sorting node forming a highest level of the sorting tree,sorting nodes in a lower level of the sorting tree having a commonnumber of sorting nodes between said uppermost sorting node and thesorting nodes in the lower level, sorting nodes between one of thesorting nodes in a lower level and the uppermost sorting node beinghereinafter referred to as higher sorting nodes assigned to the sortingnode in the lower level, and a lowest level of the sorting tree having agreatest number of nodes between the uppermost sorting node and thesorting nodes of the lower level, and wherein said sorting tree has thefollowing characteristics: a domain is fixed at least for one of saidmeasuring results in each said sorting node of the sorting tree, forsaid domain of said one of said measuring results in each said sortingnode of the sorting tree other than the uppermost sorting node of thesorting tree, a corresponding domain of said one of said measuringresults is present in a higher sorting node assigned to each saidsorting node, and the domain of said one of said measuring results ineach said sorting node of the sorting tree other than the uppermostsorting node is a subdomain or equal to the domain of the correspondingmeasuring result of the higher sorting node assigned to each saidsorting node.
 2. The method of claim 1, wherein said sorting tree hasthe further characteristic that each sorting node is assigned a sortingclass.
 3. The method of claim 1, wherein said sorting tree has thefurther characteristic that each sorting node is assigned a value spacedefined as the Cartesian product of all domains of the measuring resultsfixed in said sorting node.
 4. The method of claim 3, wherein saidsorting tree has the further characteristic that the value spaces of allassigned sorting nodes of one of said sorting nodes are disjunct.
 5. Themethod of claim 1, wherein said sorting tree has the furthercharacteristic that at least one sorting node of the sorting tree isassigned at least one report node, wherein if a measuring result is inone of said report nodes, a domain is fixed at least for said one ofsaid report nodes, and the domain of said one of said measuring resultin said one of said report nodes is a subdomain or equal to the domainof the corresponding measuring result of a higher sorting node assignedto said at least one sorting node to which said one of said report nodesis assigned.
 6. The method of claim 5, wherein said sorting tree has thefurther characteristic that each said report node is assigned a reportmessage and said report message is generated for each one of said reportnodes having a measuring result.
 7. The method of claim 5, wherein saidsorting tree has the further characteristic that each report node isassigned a value space defined as the Cartesian product of all domainsof the measuring results fixed in the report node, and each said sortingnode is assigned a value space defined as the Cartesian product of alldomains of the measuring results fixed in the sorting node to which thevalue space is assigned.
 8. The method of claim 7, wherein said sortingtree has the further characteristic that each said sorting node isassigned to a sorting space defined as the union of the value spaces ofall sorting nodes assigned to the sorting space, and a report spacedefined as the union of all value spaces of the report nodes assigned tothe sorting node to which the value space is assigned.
 9. The method ofclaim 8, wherein said sorting tree has the further characteristic thatthe report space of one of said sorting nodes is selected so that aunion of the report space and the sorting space to which said one ofsaid sorting nodes is assigned yields the value space of said one ofsaid sorting nodes corresponding to the selected report space.
 10. Themethod of claim 9, wherein said sorting tree has the furthercharacteristic that the report space of said one of said sorting nodesis selected so that the report space and sorting space of said one ofsaid sorting nodes are disjunct.
 11. The method of claim 10, whereinsaid sorting tree has the further characteristic that the value spacesof report node of said one of said sorting nodes are disjunct.
 12. Themethod of claim 10, wherein said sorting tree has the furthercharacteristic that the value spaces of all assigned sorting nodes ofsaid one of said sorting nodes are disjunct.
 13. The method of claim 5,wherein the report nodes are generated automatically, said report nodesincluding the domains for each measuring result.
 14. The method of claim13, wherein said sorting tree has the further characteristic that eachsorting node is assigned a value space defined as the Cartesian productof all domains of the measuring results fixed in said sorting node,wherein the value space of a sorting node is decomposed into subspacesalong the interval limits of the domains of the sorting nodes assignedto the sorting node, and wherein the value spaces of the report nodes,and thus the domains for the measuring results of the report nodes, areformed form the subspaces.
 15. The method of claim 14, wherein aplurality of subspaces are combined suitably into a domain of a reportnode.
 16. The method of claim 1, wherein the step of locating thesorting node comprises the step of locating the sorting class of thesorting node in the lowest level of the sorting tree at which allmeasuring results of the sheet material are within the correspondingdomains of the measuring results of the lowest level sorting node, andfurther comprising the step of assigning said sorting class to the sheetmaterial.
 17. The method of claim 16, wherein the step of locating thesorting node comprises the step of recursively checking whether saidmeasuring results are within the domains of the sorting nodes.
 18. Themethod of claim 17, wherein the step of locating the sorting nodecomprises the step of checking in a fixed order whether said measuringresults are within the domains of the sorting nodes of a level.
 19. Themethod of claim 16, wherein said sorting tree has the furthercharacteristic that at least one sorting node of the sorting tree isassigned to at least one report node, wherein a domain is fixed at leastfor one of said measuring results in each said report node, and thedomain of said one of said measuring results in the report node is asubdomain or equal to the domain of the corresponding measuring resultof the higher sorting node assigned to said at least one sorting node,and each report node is assigned a report message, and furthercomprising the step of assigning the sheet material the report messageof the at least one report node assigned to the sorting nodecorresponding to the sorting class of the sheet material.
 20. The methodof claim 19, wherein the step of locating the sorting node comprises thestep of checking in a fixed order whether said measuring results arewithin the domains of the report nodes of the at least one sorting node.21. The method of claim 1, further comprising the step of assigning asecurity value to at least one of the domains or to an internal limit ofthe measuring results in at least one of said nodes of the sorting tree.22. The method of claim 21, wherein the assigned domain or intervallimit may be changed under conditions defined by the security value. 23.The method of claim 1, further comprising the step of assigning asecurity value to at least one of said nodes.
 24. The method of claim23, wherein the domains assigned to the node may be changed underconditions defined by the security value of a respective one of saidnodes.
 25. The method of claim 23, wherein respective ones of said nodesmay be removed under conditions defined by the security value of thenode.
 26. The method of claim 23, wherein respective ones of said nodesmay be assigned further nodes under conditions defined by the securityvalue of the respective ones of said nodes.
 27. The method of claim 1,further comprising the step of assigning a marking to at least oneinterval limit of a domain of a measuring result.
 28. The method ofclaim 27, wherein at least one of said interval limits may be changed,and further comprising the step of, upon a change in an interval limitassigned a marking, changing all other interval limits assigned the samemarking.
 29. The method of claim 27, wherein at least one of themarkings is assigned a security value.
 30. The method of claim 29,wherein the markings may be changed under conditions defined by thesecurity value of the markings.
 31. The method of claim 1, wherein thesorting tree is mapped onto a rule matrix, wherein rules in said rulematrix determine which domains are included in each report node orsorting node.
 32. The method of claim 1, wherein the domains of themeasuring results of the uppermost sorting node are decomposed intopartitions, the partition limits containing at least the interval limitsof the domains of the corresponding measuring results of all othernodes.
 33. The method of claim 32, further comprising the step ofsetting up a rule matrix by assigning each node of the sorting tree arule for determining which domains are included in each said node, saidassigning step comprising the steps of marking the partitions of themeasuring results which are at least subsets of the domain of thecorresponding measuring result of the node, and using said marks toassign said rule to said node.
 34. The method of claim 33, furthercomprising the step of disposing the rules of the sorting nodes in anorder, the rules of the assigned sorting nodes being disposed in theorder of the assigned sorting nodes and before the rules of the highersorting nodes.
 35. The method of claim 34, wherein each rule of arespective said sorting node is assigned the sorting class of thesorting node.
 36. The method of claim 35, wherein the sheet material isassigned the sorting class of a first rule in the order in which atleast the partitions are marked in which all measuring results of thesheet material are located.
 37. The method of claim 33, wherein eachrule of a report node is assigned the report message of the report node.38. The method of claim 37, wherein the sheet material is assigned thereport messages of the rules in which at least the partitions are markedin which all measuring results of the sheet material are located.